Spear grasses

Australian native grasses are an extremely important component of our landscapes due to their contribution to biodiversity. They provide shelter and food for our native fauna and they also act as colonisers on disturbed sites and have a soil stabilising role for example on coastal sand dunes.

Recently many Australian native grasses are being recognised as ornamental plants in the garden. The appeal of many species is the highly decorative flowering heads of the grass which are carried on spikelets. One of my favourite groups of native grasses are the spear grasses which belong to the genus Austrostipa. They are grouped into what is termed as the cool season grasses which describes their habit of growth in the cooler months.

A couple of my favourites are Austrostipa eremophila commonly known as the desert spear grass and Austrostipa elegantissima also known as elegant spear grass. Both species are perennial grasses and are widespread throughout most of South Australia and appear to handle all sorts of soil types and even low rainfall. They grow vigorously after the opening autumn rains throughout the cooler months and are spring flowering. Their natural habit is to be dormant in summer and the foliage has a hay like appearance then, however if they are given extra water they maintain their greenery throughout the year.

In my garden I enjoy the seasonal variation with the spear grasses, lying low in summer and then suddenly reappearing with the autumn rains. I have both species growing in my personal garden in clumps and they are eye catching throughout spring. Elegant spear grass grows up to ½ a metre with white silky flower heads that dazzle as they dance in the breeze and shimmer in the sun.

I experimented over the last 18 months with clumps of desert spear grass which I planted in my alkaline heavy soil. I continued their growth throughout the summer by infrequent heavy watering and then gave them a feed of organic fertiliser coming into autumn. They have duly responded to the kind treatment by producing magnificent flowering spikes throughout this spring up to 1.2 metres high and are simply stunning.